FIELD OF THE INVENTION
[0001] The present invention relates to a photochromic material comprising a compound belonging
to the diheteroarylethene class.
BACKGROUND OF THE INVENTION
[0002] Photochromic material includes molecules or molecule aggregates which can reversibly
take the forms of two isomers having different states by photoisomerization. The photochromic
material can be utilized as photonics materials such as optical memory media and optical
display materials, because the photochromic material can change not only its color
but also its various other physical properties such as refractive index, dielectric
constant, and oxidation/reduction potential under irradiation of light.
[0003] Japanese Unexamined Patent Publication No.
H3-261782 discloses a photochromic material belonging to the diheteroarylethane class, having
methoxy groups at two reactive positions participating in ring closing/ring opening
reactions, as expressed by the following formula:
[0004] The record or image of the optical memory medium or optical display material of the
photochromic material may disappear under ambient light such as a room light. When
the quantum yield of ring opening reaction (hereinafter, referred to as "ring opening
quantum yield") of a compound, belonging to the diarylethene class, in the closed-ring
form is in the order of 10
-2, the record or image will disappear almost completely in several hours under fluorescent
room light.
[0005] The aforementioned compound belonging to the diheteroarylethene class disclosed in
Japanese Unexamined Patent Publication No.
H3-261782 has a ring opening quantum yield of 3.3 × 10
-2, which is larger than 10
-2.
DISCLOSURE OF THE INVENTION
[0006] A photochromic material of the present invention comprises a compound, belonging
to the diheteroarylethene class, represented by the following general formula [I]:
[0007] In the general formula [I], A represents substituents [i] or [ii] shown below, and
B represents substituents [iii] or [iv] shown below.
[0008] In the substituents [i] and [ii] , R
1 represents an alkoxy group, and R
2 represents -Q-Ar. Q represents a direct bond or an arbitrary divalent group, and
Ar represents an aromatic hydrocarbon ring or an aromatic heterocycle, which are optionally
substituted. R
3 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a fluoroalkyl
group, a cyano group, or an aryl group which is optionally substituted, and Y represents
-O- or -S-.
[0009] In the substituents [iii] and [iv], R
4 represents an alkoxy group, and R
5 represents -Q-Ar. Q represents a direct bond or an arbitrary divalent group, and
Ar represents an aromatic hydrocarbon ring or an aromatic heterocycle, which are optionally
substituted. R
6 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a fluoroalkyl
group, a cyano group, or an aryl group which is optionally substituted, and Z represents
-O- or -S-.
[0010] The photochromic material of the present invention has a ring opening quantum yield
of 10
-3 or lower.
DESCRIPTION OF THE.PREFERRED EMBODIMENTS
[0011] Hereinafter, the present invention will be described in detail
[0012] A photochromic material of the present invention comprises a compound, belonging
to the diheteroarylethene class, represented by the abovementioned general formula
[I].
[0013] In the substituents [i]-[iv] of the general formula [I], R
1 and R
4 each represent independently alkoxy group with 1-3 carbon atoms such as methoxy group
and ethoxy group, preferably a methoxy group or an ethoxy group, more preferably a
methoxy group.
[0014] R
2 and R
5 each represent independently -Q-Ar. Q represents a direct bond or an arbitrary divalent
group, and Ar represents an aromatic hydrocarbon ring or an aromatic heterocycle,
which are optionally substituted. In preferable structures, a conjugated system extends
from both heteroaryl rings of the diarylethene structure to substituents R
2 and R
5. In the general formula [I] , Q preferably comprises a direct bond, -(-CH=CH-)
n- (i.e. a polyethylene group) (wherein n = 1-5), or -(C≡C-)
n- (i.e. a polyacetylene group) (wherein n = 1-5), and Ar preferably comprises a group
consisting of 5-or 6-member ring or a group consisting of two or three 5- or 6-member
rings bonded directly or condensed, each of the groups being optionally substituted.
When Ar has a substituent, the substituent includes a linear or branched alkyl group
with 1-10 carbon atoms such as methyl group, ethyl group, butyl group, and hexyl group;
a linear or branched alkoxy group with 1-10 carbon atoms such as methoxy group, ethoxy
group, butoxy group, and hexyloxy group; a halogen atom such as fluorine atom and
chlorine atom; and linear or branched fluoroalkyl group with 1-6 carbon atoms such
as trifluoromethyl group, pentafluoroethyl group, 2-fluoroethyl group, 2,2-difluoroethyl
group, perfluoro-n-hexyl group, and 2-(perfluorobutyl)ethyl group.
[0015] In a diarylethene structure, it is preferable that the heteroaryl rings (the heterocycles
comprising -Y- or -Z-, shown in structures [i]-[iv]) and R
2 or R
5 form a same plane. For this purpose, it is preferable that the diarylethene structure
represented by the general formula [I] has a relatively low-volumed group at the ortho-position
of Ar (ortho-position relative to the position at which Ar is bonded to heteroaryl
ring)
[0018] In accordance with the present invention, the ring opening quantum yield can be substantially
decreased by introducing the above described Ar groups at R
2 and R
5, together with alkoxy groups introduced at R
1 and R
4.
[0019] R
3 and R
6 each represent independently, for example, a hydrogen atom; a linear or branched
alkyl group with 1-10 carbon atoms such as methyl group, ethyl group, butyl group,
and hexyl group; a linear or branched alkoxy group with 1-10 carbon atoms such as
methoxy group, ethoxy group, butoxy group, and hexyloxy group; a halogen atom such
as fluorine atom and chlorine atom; a linear or branched fluoroalkyl group with 1-6
carbon atoms such as trifluoromethyl group, pentafluoroethyl group, 2-fluoroethyl
group, 2,2-difluoroethyl group, perfluoro-n-hexyl group, and 2-(perfluorobutyl) ethyl
group; a cyano group; and an aryl group such as phenyl group and tosyl group which
are optionally substituted. A relatively low-volumed group is preferable for R
3 and R
6, a linear alkyl group being especially preferable.
[0021] Each of the above compounds gives rise to ring closing reaction under irradiation
of ultraviolet light, efficiently developing color which does not disappear in several
hours in room environment, but can stand stably for a longer period of time.
[0022] Hereinafter, the present invention will be described more specifically by way of
Synthesis Examples and Examples.
Synthesis Example 1: Synthesis of 1,2-bis[2-methoxy-5-phenyl-3-thienyl]perfluorocyclopentene
(1-1) Synthesis of 3,5-dibromo-2-methoxythiophene
[0023]
[0024] 16 g (145 mmol) of 2-methoxythiophene was added into 40 ml of carbon tetrachloride.
Then, 51 g (290 mmol) of N-bromosuccinimide and 250 ml of carbon tetrachloride were
slowly added into it while being stirred in an ice water bath. After stirred overnight
without the water bath, the solution was cooled again in an ice water bath and was
filtered by suction filtration to eliminate solids. The filtrate was extracted using
chloroform, was washed successively with a sodium bicarbonate aqueous solution and
water, and was dried with addition of magnesium sulfate. The dried extract was condensed
after removing magnesium sulfate by filtration. By developing the product with hexane
on a silica gel column, a colorless liquid was obtained (R
f = 0.65). Purification of the liquid by vacuum distillation (b.p.= 90°C, 8 mmHg) gave
the object compound, 3,5-dibromo-2-methoxythiophene. The yield was 24.6 g in weight
and 62.3 % in percentage.
[0025] 1H NMR (200 MHz, CDCl
3, TMS): ,3.93 (s, 3H), 6.75 (s, 1H) ,
MSm/z =270, 272, 274 (M
+)
(1-2) Synthesis of 3-bromo-2-methoxy-5-phenylthiophene
[0026]
[0027] 250 ml of anhydrous THF was added into 24 g (88 mmol) of 3,5-dibromo-2-methoxythiophene
and was cooled to be -78°C with dry ice-methanol. Then, 56 ml (92 mmol) of a solution
containing 15 % n-butylithium hexane was slowly dripped into it. After being stirred
for 1 hour, 32 ml (123 mmol) of tri-n-butyl borate was slowly dripped into it and
stirred for 2 hours. After being returned to a room temperature, 90 ml of 20 wt% Na
2CO
3, 18 g (88 mmol) of iodobenzene, and 4.4 g (0.36 mmol) of Pd(Ph
3P)
4 were added to the solution and refluxed for 5 hours at 70°C. The reaction solution
was extracted with ether, washed with a salt solution, and dried with addition of
magnesium sulfate. The dried extract was condensed after removing magnesium sulfate
by filtration. By developing the product with hexane on a silica gel column, a colorless
solid 3-bromo-2-methoxy-5-phenylthiophene was obtained (R
f = 0.35). The yield was 15 g in weight and 63 % in percentage.
[0028] 1H NMR (400 MHz, CDCl
3, TMS): ,4.00 (s, 3H) , 6.98 (s, 1H), 7.2-7.5 (m, 5H)
MSm/z = 268, 270 (M
+)
Anal. Calcd for C
11H
9BrOS: C=49.09, H=3.37
Found: C=49.20, H=3.38
(1-3) Synthesis of 1,2-bis[2-methoxy-5-phenyl-3-thienyl]perfluorocyclopenten e (compound
1)
[0029]
[0030] 140 ml of anhydrous THF was added into 14 g (52 mmol) of 3-bromo-2-methoxy-5-phenylthiophene
under argon atmosphere and was cooled to -60°C or lower in dry ice-methanol bath.
Then, 36 ml (52 mmol) of a solution containing 15 % n-butylithium hexane was slowly
dripped into it and stirred for 1 hour. Then, 3.5 ml (26 mmol) of perfluorocyclopentene
in 10 ml of anhydrous THF was slowly dripped into it at -60°C or lower and was stirred
for 2 hours. After being quenched by addition of methanol, the reaction solution was
washed with 1N hydrochloric acid and was extracted with ether. The organic phase was
washed with water, was dried with magnesium sulfate, and was condensed after magnesium
sulfate was removed by filtration. By developing the product with hexane:chloroform
= 9:1 solvent on a silica gel column, the compound 1 was isolated (R
f = 0.56) . The yield was 7.2 g in weight and 50 % in percentage.
[0031] 1H NMR (400 MHz, CDCl
3, TMS): ,3.71 (s, 3H) , 7.15 (s, 1H), 7.2-7.5 (m, 5H)
MSm/z = 552 (M
+)
1H NMR (200 MHz, CDCl
3, TMS) : "3.71 (s, 6H) , 7.16 (s, 2H), 7.2-7.5 (m, 10H)
Anal. Calcd for C
27H
18F
6O
2S
2: C=58.69, H=3.28
Found: C=58.87, H=3.37
Synthesis Example 2: Synthesis of 1,2-bis[2-ethoxy-5-phenyl-3-thienyl]perfluorocyclopentene
(2-1) Synthesis of 5-methoxy-2-phenylthiophene
[0032]
[0033] 15 g (69 mmol) of 2-iodothiophene, 9.4 g (140 mmol) of sodium ethoxide, 2.7 g (35
mmol) of copper oxide, and 80 ml of anhydrous ethanol were added into a flask under
argon atmosphere and were refluxed for two nights. Further, 7.0 g (100 mmol) of sodium
ethoxide and 57 ml (0.35 mmol) of potassium iodide were added to it until material
spots disappeared in TLC, and were refluxed for 7 hours. The reaction solution was
returned to a room temperature, was filtered by suction filtration, and was mixed
with ice water. The reaction solution was then extracted with ether, was washed with
a salt solution, and was dried with magnesium sulfate. After filtering out the magnesium
sulfate and evaporating the solvent, the product was subjected to vacuum distillation
(b.p.= 56°C, 8 mmHg) to give a colorless oil of 5-methoxy-2-phenylthiazole. The yield
was 3 .1 g in weight and 57 % in percentage.
MSm/z = 128 (M
+)
1H NMR (200 MHz , CDCl
3, TMS) : "1.41 (t,
J=7 Hz, 3H) , 4.09 (q,
J=7 Hz, 2H) , 6.20 (d,
J=3.6 Hz, 1H) , 6.53 (d,
J=5.8 Hz, 1H) , 6.71 (t,
J=4.8 Hz, 1H)
(2-2) Synthesis of 3,5-dibromo-2-ethoxythiophene
[0034]
[0035] 40 ml of carbon tetrachloride with 8.5 g (48 mmol) of N-bromosuccinimide was slowly
added into 8 ml of carbon tetrachloride with 3 .1 g (24 mmol) of 2-ethoxythiophene
while being stirred in an ice water bath. Then, the ice water bath was removed and
stirring was continued overnight. The reaction solution was cooled in an ice water
bath and was filtered to remove solids by suction filtration. The reaction solution
was then extracted with chloroform, was washed with sodium bicarbonate, sodium thiosulfate,
and water, and was dried with magnesium sulfate. After filtering out the magnesium
sulfate and evaporating the solvent, the product was developed with hexane on a silica
column to give thin yellow oil of 3.5-dibromo-2-ethoxythiophene (R
f = 0.48). The yield was 6.5 g in weight and 94 % in percentage.
MSm/z = 284, 286, 288 (M
+)
1H NMR (200 MHz, CDCl
3, TMS) : "1.43 (t,
J=7 Hz, 3H) , 4.13 (q,
J=7 Hz, 2H), 6.75 (s, 1H),
Anal. Calcd for C
6H
6Br
2OS: C=25.20, H=2.11
Found: C=25.50, H=2.14
(2-3) Synthesis of 3-bromo-2-ethoxy-5-phenylthiophene
[0036]
[0037] 150 ml of anhydrous THF and 6.5 g (23 mmol) of 3,5-dibromo-2-ethoxythiophene was
added into a flask under argon atmosphere. Then, 15 ml (25 mmol) of a solution containing
15 % n-butylithium hexane was slowly dripped into it at -78°C. After being stirred
for 1 hour at -78°C, 9.1 ml (34 mmol) of tri-n-butyl borate was slowly dripped into
it and was stirred for 1.5 hours. After being returned to a room temperature and quenched
with water, 4.6 g (23 mmol) of iodobenzene, 1.1 g (0.95 mmol) of Pd(PPh
3)
4, and 50 ml of 20 wt% Na
2CO
3 aqueous solution was added to the solution and was refluxed overnight at 70°C. The
reaction solution was extracted with ether, was washed with a salt solution, and was
dried with magnesium sulfate. After filtering out the magnesium sulfate and evaporating
the solvent, the product was developed with hexane on a silica column to give 3-bromo-2-ethoxy-5-phenylthiophene
(R
f = 0.31). The yield was 4.9 g in weight and 76 % in percentage.
MSm/z = 282, 284 (M
+)
1H NMR (200 MHz, CDCl
3) : "1.48 (t,
J=7 Hz, 3H) , 4.21 (q,
J=7 Hz, 2H), 6.98 (s, 1H), 7.25-7.49 (m, 5H),
Anal. Calcd for C
12H
11BrOS: C=50.90, H=3.92
Found: C=51.17, H=3.89
(2-4) Synthesis of 1,2-bis[2-ethoxy-5-phenyl-3-thienyl]perfluorocyclopentene (compound
2)
[0038]
[0039] 4.9 g (17 mmol) of 3-bromo-2-ethoxy-5-phenylthiophene and 45 ml of anhydrous THF
was added into a flask under argon atmosphere. Then, 12 ml (19 mmol) of a solution
containing 15% n-butylithium hexane was slowly dripped into it at -78°C. After being
stirred for 1.5 hours at -78°C, 5 ml of anhydrous THF with 1.2 ml (34 mmol) of perfluorocyclopentene
was slowly dripped into it and was stirred for 3 hours. After being returned to the
room temperature and being quenched with water, the reaction solution was washed with
1N hydrochloric acid. The reaction solution was extracted with ether, was washed with
a salt solution, and was dried with magnesium sulfate. After filtering out the magnesium
sulfate, the product was developed with hexane:chloroform = 7:3 solvent on a silica
gel column to isolate
1,2-bis[2-ethoxy-5-phenyl-3-thienyl]perfluorocyclopentene that is the compound 2.
The yield was 1.8 g in weight and 36 % in percentage.
MSm/z = 580 (M
+)
1H NMR (200 MHz, CDCl
3) : "1.08 (t, J=7 Hz, 6H) , 3.92 (q, J=7 Hz, 4H), 7.22 (s, 2H), 7.26-7.51 (m, 10H),
Anal. Calcd for C
29H
22N
2F
6O
2S
2: C=59.99, H=3.82
Found: C=60.03, H=3.80
Synthesis Example 3: Synthesis of 1,2-bis[5-methoxy-2-phenyl-3-thiazoyl]perfluorocyclopente
ne
(3-1) Synthesis of 5-methoxy-2-phenylthiazole
[0040]
[0041] 1.0 g (5.2 mmol) of benzoylglycin methyl ester and 1.4 g (6.4 mmol) of diphosphorous
pentasulfide was added quickly into a reaction vessel. After that, anhydrous chloroform
(15 ml) was also added and heated to around 80°C. When decrease in hydrogen sulfide
generation and white precipitate formation in the reaction solution were observed,
an argon balloon was attached and the solution was refluxed for 24 hours. After completion
of reaction, the precipitate was dissolved by adding an aqueous solution of strong
alkali to the solution, and the organic phase was extracted with dichloromethane,
followed by drying with addition of magnesium sulfate and removal of solvent. The
product was developed with ethyl acetate:hexane = 5:5 solvent on a silica column to
give 5-methoxy-2-phenylthiazole (R
f = 0.40). The yield was 566 mg in weight and 57 % in percentage.
MSm/z = 191 (M
+)
1H NMR (200 MHz, CDCl
3) : "7.84-7.80 (m, 2H), 7.60-7.40 (m, 3H) , 6.65 (br s, 1H) , 4.27 (d,
J=4.8Hz, 2H), 3.82 (s, 3H) ,
Anal. Calcd for C
10H
9NOS: C=62.80, H=4.74, N=7.32
Found: C=62.64, H=4.78, N=7.34
(3-2) Synthesis of 4-bromo-5-methoxy-2-phenylthiazole
[0042]
[0043] 400 mg (2.1 mmol) of N-bromosuccinimide was added into 10 ml of anhydrous chloroform
with 400 mg (2.1 mmol) of 5-methoxy-2-phenylthiazole under 0°C condition and was stirred
for 4 hours at a room temperature. After completion of reaction, the organic phase
was extracted with ethyl acetate, and was dried with addition of magnesium sulfate.
After removing the solvent, the product was developed with ethyl acetate:hexane =
1:3 solvent on silica column to give 4-bromo-5-methoxy-2-phenylthiazole (R
f=0.50). The yield was 550 mg in weight and 97 % in percentage.
MSm/z = 271 (M
+)
1H NMR (200 MHz, CDCl
3, TMS): "7.85-7.78 (m, 2H), 7.45-7.36 (m, 3H), 4.03 (s, 3H),
Anal. Calcd for C
10H
8NOSBr: C=44.46, H=2.98, N=5.18
Found: C=44.56, H=2.99, N=5.19
(3-3) Synthesis of 1-[5-methoxy-2-phenyl-3-thiazoil]perfluorocyclopentene
[0044]
[0045] 8 ml of anhydrous.THF was added into 540 mg (2.0 mmol) of 4-bromo-5-methoxy-2-phenylthiazole
under argon atmosphere and was cooled to -78°C or lower with a methanol solution of
dry ice. 1.3 ml (2 .1 mmol) of a solution containing 15% n-butylithium hexane was
dripped slowly into it and was stirred for 15 minutes. Then, 0.2 ml (0.93 mmol) of
perfluorocyclopentene was added in 2 ml of anhydrous THF, was slowly dripped into
it at -78 °C or lower, and was stirred for 2.5 hours. After being quenched by addition
of water, the reaction solution was extracted with ether. The organic phase was washed
with water and was dried with magnesium sulfate, was filtered to remove the magnesium
sulfate, and was concentrated. The product was developed with hexane:ethyl acetate
= 1:3 solvent on a silica gel column to isolate 1-[5-methoxy-2-phenyl-3-thiazoil]perfluorocyclopentene
(R
f = 0.30) . The yield was 510 mg in weight and 72 % in percentage.
MS m/z = 383 (M
+)
1H NMR (200 MHz, CDCl
3, TMS): "7.88-7.80 (m, 2H), 7.48-7.40 (m, 3H), 4.13 (s, 3H),
Anal. Calcd for C
15H
8NOSF
7: C=47.00, H=2.10, N=3.65
Found: C=47.25, H=2.08, N=3.66
(3-4) Synthesis of 1,2-bis[5-methoxy-2-phenyl-3-thiazoyl]perfluorocyclopente ne (compound
3)
[0046]
[0047] 8 ml of anhydrous THF was added into 540 mg (2.0 mmol) of 4-bromo-5-methoxy-2-phenylthiazole
under argon atmosphere and was cooled to -78°C or lower with a methanol solution of
dry ice. 1.3ml (2.1 mmol) of a solution containing 15% n-butylithium hexane was dripped
slowly into it and was stirring for 15 minutes. Then, 510 mg (1.33 mmol) of 1-[5-methoxy-2-phenyl-3-thiazoil]perfluorocyclopentene
was added into 2 ml of anhydrous THF, was slowly dripped into it at -78°C or lower,
and was stirred for 2.5 hours. After quenching by addition of water, the solution
was extracted with ether. The organic phase was washed with water, was dried with
magnesium sulfate, was filtered to remove the magnesium sulfate, and was concentrated.
The product was developed with hexane:ethyl acetate = 3:7 solvent on a silica gel
column to isolate
1,2-bis [5-methoxy-2-phenyl-3-thiazoil]perfluorocyclopente ne that is the compound
3 (R
f = 0.10). The yield was 540 mg in weight and 68 % in percentage.
MS m/z =554 (M
+)
1H NMR (200 MHz, CDCl
3, TMS): "7.86-7.74 (m, 4H), 7.44-7.35 (m, 6H), 3.83 (s, 6H),
Anal. Calcd for C
25H
16N
2O
2S
2F
6: C=54.15, H=2.91, N=5.05
Found: C=54.25, H=2.97, N=5.10
Example 1
[0048] The compound 1 synthesized in Synthesis Example 1 was dissolved in hexane. This solution
was irradiated with light of 313 nm. The solution developed blue color of which absorption
maximum was observed at 625 nm (" = 1.5 × 10
4 M
-1 cm
-1). The generation quantum yield of the colored substance (in the closed-ring form)
was determined to be 0.44. The blue color showed no remarkable fading even when irradiated
with visible light. The ring opening quantum yield corresponding to fading was determined
to be 1.7 × 10
-5.
(Measuring procedure for ring closing quantum yield)
[0049]
- (1) Hexane solutions in the open-ring forms of the compound 1 and of
1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene (the compound 2) as a comparative
sample were prepared. The both solutions were adjusted to make their absorbance at
irradiation wavelength of 309 nm (absorption maximum wavelength of the compound 1
in the open-ring form) to be the same level within a range from 0.2 to 0.3.
- (2) The solution volumes in absorption cells were equalized.
- (3) In measurement, the absorbance changes of the closed form compounds at absorption
maximum wavelength in visible light region (the compound 1: 625 nm, the compound 2:
575 nm) were detected. The compound 1 and the compound 2 as a comparative sample were
irradiated with light of 309 nm using a xenon lamp, and measurements were made for
10 points in absorbance range of detected wavelength of about 0-0.1.
- (4) The absorbance changes relative to time were plotted, and, from comparison of
inclinations for the both compounds, a ring closing quantum yield of 0.44 was obtained
for the compound 1 (the quantum yield of the compound 2 was 0.59).
[0050] A quantitative measurement of fading tendency was conducted as follows . The fading
by light was hardly observed.
(Measuring procedure for ring opening quantum yield)
[0051]
- (1) A hexane solution of the compound 1 was prepared and was irradiated with ultraviolet
light (wavelength 313 nm) to adjust its absorbance at a wavelength of 625 nm, which
is the absorption maximum wavelength in visible light region, to be about 0.5. The
hexane solution was irradiated with a light of 625 nm using a xenon lamp and was measured
for every time period for which the absorbance may be changed by about 0.01.
- (2) Fulgide was used as a comparative sample. A toluene solution of the fulgide was
prepared and was irradiated with light of 492 nm. The absorbance at a wavelength 492
nm was measured at several points in the approximate changing range of from 0.5 to
0.2, similarly to the case of the compound 1.
- (3) Using an actinometer, the light quantities at wavelengths of 692 nm and of 492
nm were measured.
- (4) Values of log(10A-1) (wherein A represents absorbance) were plotted against time. From the inclination
of the plotting which was corrected using the values of light quantities obtained
in (3), the relative quantum yield was determined. As a result, the quantum yield
of fading reaction (ring opening reaction) was determined to be 1.7 × 10-5. Even when the solution was exposed to ambient light for three months, no fading
(ring opening reaction) was observed.
Example 2
[0052] The compound 1 (10 mg) synthesized in Synthesis Example 1 and 200 mg of polystyrene
were dissolved in 3 mL of toluene, and the solution was cast on a Teflon plate to
form a polystyrene film having a thickness of 500 ,m. Irradiation of light of 366
nm onto the film instantly colored the film in blue color. This blue color showed
no fading (ring opening reaction) even when exposed to ambient light for three months.
Example 3
[0053] The compound 2 synthesized in Synthesis Example 2 was dissolved in toluene, and the
solution was irradiated with light of 313 nm. The solution developed blue color of
which absorption maximum was observed at 625 nm (" = 1.3 x 10
4 M
-1 cm
-1). The generation quantum yield of the colored substance (in the closed form) was
determined to be 0.48. The blue color showed no remarkable fading even when irradiated
with visible light. The ring opening quantum yield corresponding to fading was determined
to be 2.5 × 10
-4.
(Measuring procedure for ring closing quantum yield)
[0054]
- (1) Hexane solutions in the open-ring forms of the compound 2 and of fulgide as a
comparative sample were prepared. The both solutions were adjusted to make their absorbance
at irradiation wavelength of 310 nm (absorption maximum wavelength of the compound
3 in the open-ring form) to be the same level within a range from 0.2 to 0.3.
- (2) The solution volumes in absorption cells were equalized.
- (3) In measurement, the absorbance changes of closed form compounds at absorption
maximum wavelength in visible light region (the compound 2: 625 nm, the fulgide: 492
nm) were detected. The compound 2 and the fulgide were both irradiated with light
of 310 nm using a xenon lamp, and measurements were made for 10 points in absorbance
range of detected wavelength of from about 0 to about 0.1.
- (4) The absorbance changes relative to time were plotted and, from comparison of inclinations
for both compounds, a ring closing quantum yield of 0.48 was obtained for the compound
2 (the quantum yield of fulgide was 0.20).
[0055] A quantitative measurement of fading tendency was conducted as follows. The fading
by light was hardly observed.
(Measuring procedure for ring opening quantum yield)
[0056]
- (1) A hexane solution of the compound 2 was prepared and was irradiated with ultraviolet
light (wavelength 313 nm) to adjust its absorbance at a wavelength of 625 nm, which
is the absorption maximum wavelength in visible light region, to be about 0.4. The
hexane solution was irradiated with a light of 625 nm using a xenon lamp and was measured
for every time period for which the absorbance may be changed by about 0.01.
- (2) Fulgide was used as a comparative sample. A toluene solution of the fulgide was
prepared and was irradiated with light of 492 nm. The absorbance at a wavelength 492
nm was measured at several points in the approximate changing range of from 0.4 to
0.2, similarly to the case of the compound 2.
- (3) Using an actinometer, the light quantities at wavelengths of 625 nm and of 492
nm were measured.
- (4) Values of log (10A-1) (wherein A represents absorbance) were plotted against time. From the inclination
of the plotting which was corrected using the values of light quantities obtained
in (3), the relative quantum yield was determined. As a result, the quantum yield
of fading reaction (ring opening reaction) was determined to be 2.5 × 10-4.
Example 4
[0057] The compound 3 synthesized in Synthesis Example 3 was dissolved in toluene, and the
solution was irradiated with light of 313 nm. The solution developed violet color
of which absorption maximum was observed at 555 nm (" = 1.3 × 10
4 M
-1 cm
-1). The generation quantum yield of the colored substance (in the closed-ring form)
was determined to be 0.29. The violet color showed no remarkable fading even when
irradiated with visible light. The ring opening quantum yield corresponding to fading
was determined to be 3.3 × 10
-4.
(Measuring procedure for ring closing quantum yield)
[0058]
- (1) Toluene solutions in the open-ring forms of the compound 3 and of fulgide as a
comparative sample were prepared. The absorbance of the both solutions at irradiation
wavelength of 313 nm were adjusted to a same level within a range from 0.2 to 0.3.
- (2) The solution volumes in absorption cells were equalized.
- (3) In measurement, the absorbance changes of closed form compounds at absorption
maximum wavelength in visible light region (compound 3: 555 nm, fulgide: 492 nm) were
detected. The compound 3 and the fulgide were both irradiated with light of 313 nm
using a xenon lamp, and measurements were made for 10 points in absorbance range of
detected wavelength of from about 0 to about 0.1.
- (4) The absorbance changes relative to time were plotted and, from comparison of inclinations
for both compounds, a ring closing quantum yield of 0.29 was obtained for the compound
3 (the quantum yield of fulgide was 0.20).
[0059] A quantitative measurement of fading tendency was conducted as follows . The fading
by light was hardly observed.
(Measuring procedure for ring opening quantum yield)
[0060]
- (1) A toluene solution of the compound 3 was prepared and was irradiated with ultraviolet
light (wavelength 313 nm) to adjust its absorbance at a wavelength of 555 nm, which
is the absorption maximum wavelength in visible light region, to be about 0.4. The
hexane solution was irradiated with a light of 555 nm using a xenon lamp and was measured
for every time period for which the absorbance may be changed by about 0.01.
- (2) Fulgide was used as a comparative sample. A toluene solution of the fulgide was
prepared and was irradiated with light of 492 nm. The absorbance at a wavelength 492
nm was measured at several points in the approximate changing range of from 0.4 to
0.2, similarly to the case of the compound 3.
- (3) Using an actinometer, the light quantities at wavelengths of 555 nm and of 492
nm were measured.
- (4) Values of log(10A-1) (wherein A represents absorbance) were plotted against time. From the inclination
of the plotting which was corrected using the values of light quantities obtained
in (3), the relative quantum yield was determined. As a result, the quantum yield
of fading reaction (ring opening reaction) was determined to be 3.3 x 10-4.
INDUSTRIAL APPLICABILITY
[0061] As described in detail hereinabove, according to the present invention, a photochromic
material is provided which has a substantially low ring opening quantum yield, practically
no fading problem under ambient light, and an excellent long-time stability of recorded
or displayed information.
[0062] The photochromic material of the present invention has possible applications not
only for the production of optical memory media and optical display materials, but
also to novel optical elements.
1. Photochromes Material, das eine Verbindung umfasst, die zu der Diheteroarylethen-Klasse
gehört, die durch die folgende allgemeine Formel [I] dargestellt wird:
wobei in der allgemeinen Formel [I] A die folgenden Substituenten [i] oder [ii] darstellt
und B die folgenden Substituenten [iii] oder [iv] darstellt:
wobei in den Substituenten [i] und [ii] R
1 eine Alkoxygruppe darstellt, R
2 -Q-AR darstellt, worin Q eine direkte Bindung oder eine beliebige divalente Gruppe
darstellt und Ar einen aromatischen Kohlenwasserstoffring oder einen aromatischen
Heterocyclus darstellt, die gegebenenfalls substituiert sind, R
3 ein Wasserstoffatom, eine Alkylgruppe, eine Alkoxygruppe, ein Halogenatom, eine Fluoralkylgruppe,
eine Cyanogruppe oder eine Arylgruppe, die gegebenenfalls substituiert ist, darstellt
und Y -O- oder -S- darstellt; und
in den Substituenten [iii] und [iv] R
4 eine Alkoxygruppe darstellt, R
5 -Q-Ar darstellt, worin Q eine direkte Bindung oder eine beliebige divalente Gruppe
darstellt und Ar einen aromatischen Kohlenwasserstoffring oder einen aromatischen
Heterocyclus darstellt, die gegebenenfalls substituiert sind, R
6 ein Wasserstoffatom, eine Alkylgruppe, eine Alkoxygruppe, ein Halogenatom, eine Fluoralkylgruppe,
eine Cyanogruppe oder eine Arylgruppe, die gegebenenfalls substituiert ist, darstellt
und Z -O- oder -S- darstellt.
2. Photochromes Material, wie es in Anspruch 1 beansprucht ist, wobei die Ringöffnungs-Quantumausbeute
10-3 oder niedriger ist.
3. Photochromes Material, wie es in Anspruch 1 oder 2 beansprucht ist, wobei R1 und R4 in den Substituenten [i]-[iv] der allgemeinen Formel [I] jeweils unabhängig eine
Alkoxygruppe mit 1-3 Kohlenstoffatomen umfassen.
4. Photochromes Material, wie es in Anspruch 3 beansprucht ist, wobei R1 und R4 jeweils eine Methoxygruppe umfassen.
5. Photochromes Material, das in einem der Ansprüche 1-4 beschrieben ist, wobei Q in
Q-Ar, das R2 und R5 in den Substituenten [i]-[iv] der allgemeinen Formel [I] entspricht, jeweils unabhängig
eine direkte Bindung, -(-CH=CH-)n- (d.h. eine Polyethylengruppe) (worin n = 1-5) oder -(C≡C-)n- (d.h. eine Polyacetylengruppe) (worin n = 1-5) umfasst, wobei Ar einen einzelnen
5- oder 6-gliedrigen Ring oder zwei oder drei 5- oder 6-gliedrige Ringe direkt gebunden
oder kondensiert umfasst, wobei jeder der Ringe gegebenenfalls substituiert ist.
8. Photochromes Material, das in einem der Ansprüche 1 bis 7 beschrieben ist, wobei R3 und R6 jeweils unabhängig eine lineare Alkylgruppe umfassen.